On 16/06/09 14:29, Markus GRASS wrote:
Moritz Lennert wrote:
All features without any cat value display in all layers. As Paul
mentioned, you have to explicitely use the cat= parameter to only
display features with cat values in that layer. It is debatable
whether there should be a flag to indicate "only show features with
cat values in the chosen layer", or whether this should actually be
the default with a flag indicating "also show features without cat
values". I think the first would be more appropriate and would be a
more convenient way than using cat=1-9999.
It seems that this behaviour depends on the feature types defined with
type option. In a quick test with the spearfish dataset, boundaries
having no cats are always displayed by default, but if I select layer=2
type=area instead of type=point,line,boundary,centroid,area,face, I get
only the areas with a cat value in layer 2 and no boundaries, no lines,
nothing else is displayed, and it is not necessary to use cat=1-9999.
But how you deal with the situation I described, i.e. one boundary
segment of the polygons has a cat value in layer 2 ? I.e.
GRASS 6.5.svn (spearfish60):~ > v.category testlayers option=report
Layer/table: 1/testlayers
type count min max
point 0 0 0
line 0 0 0
boundary 0 0 0
centroid 2 1 2
area 0 0 0
all 2 1 2
Layer: 2
type count min max
point 0 0 0
line 0 0 0
boundary 1 1 1
centroid 0 0 0
area 0 0 0
all 1 1 1
d.vect testlayers layer=1
d.vect testlayers layer=2 type=boundary cat=1-9999 col=red width=3
gives:
http://geog-pc40.ulb.ac.be/grass/misc/testlayers1.png
I need to declare either the boundary type (or no type at all) to see
anything in layer 2, but then it shows all boundaries:
http://geog-pc40.ulb.ac.be/grass/misc/testlayers2.png
Moritz
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